The present invention relates generally to a novel and improved air bag mounting system. More specifically, the invention concerns an arrangement for retaining a preassembled state among several elements of an air bag assembly useful for maintaining the integrity of the subassembly, thus defined, during the final assembly operations required for manufacture and installation of the air bag in an automobile.
Given the present, high demand for air bags in cars, the utility of the invention will become clear upon reading the following description.
An air bag subassembly generally consists of four elements: a housing, an air bag, a retaining ring, and an inflator. Given the compartmentalized, assembly line manufacturing procedure inherent in automobile factories today, the first three of these elements, usually, are pre-assembled at one area of the factory, and transported, in pre-assembled form (i.e. as a subassembly), to another part of the factory for final assembly with the inflator and installation in an automobile. In some instances, the four air bag elements are assembled by an air bag manufacturer, and sold, as a unit in their assembled form, to an automobile manufacturer. Both of these manufacturing procedures require some handling and transportation of the first three above-mentioned elements of the air bag subassembly in their pre-assembled form.
Because of this handling and transportation, it is necessary that the three elements of the air bag subassembly be joined firmly together, so that they will not become dislodged before final assembly with the inflator, prior to installation in an automobile. In the past, the retaining ring was pre-assembled with individual, rivets independent to the retaining ring which were "peened over" (Put simply, expanding and flattening portions of the rivets adjacent to the retaining ring) to hold the retaining ring in assembly with the housing, with the air bag sandwiched in between, so as to insure a solid combination. This method, however, has certain drawbacks.
The riveting process employed individual, independent rivets, and was another step in the manufacturing process, which served to delay production by increasing the time needed to produce an air bag subassembly. Workmen sometimes spend an inordinate amount of time trying to line up corresponding holes and inserting rivets therein.
Additionally, when a workman tried to insert a rivet, another, previously inserted rivet sometimes fell out, necessitating repetition of steps already taken, further increasing the time taken in pre-assembly. The riveting also added to the production costs of the air bag, as the individual rivets had to be first positioned properly and then peened over to effect pre-assembly.
Furthermore, when the retaining ring was riveted to the housing, there was some danger of damaging the air bag during the handling and riveting operations, thereby compromising the structural integrity of the air bag. If the structural integrity of the air bag is compromised, the entire assembly must be discarded, adding further production costs.
Air bag inflation takes place in a time period on the order of one-twentieth of a second. Accordingly, forces of great magnitude are generated during the inflation process. Therefore, it is important that the retaining ring be able to firmly hold the air bag in place so as to prevent blow-by of the inflating material. Also, due to the great forces present during inflation, it is important that the air bag assembly be reinforced to prevent deformation of the retaining ring.
Accordingly, some alternative means is desired that is capable of effectively joining the first three elements of an air bag assembly into a subassembly, before final assembly with the inflator, and subsequent installation of that subassembly in an automobile, or other vehicle, so that the elements of the assembly will not become dislodged during handling and transportation. Preferably, such means should be low in cost, and be relatively simple, taking little time to employ. Most importantly, the means, or its employment cannot compromise the structural integrity of the air bag in any way. Additionally, the alternative means would have means for preventing blow-by of inflation material, and provide reinforcing means for the retaining ring.